The numerous and varied beneficial properties of carbon nanotubes have been widely heralded, including their high modulus, high strain-to-failure ratio, and high current density. Since these benefits are well documented, an in-depth discussion thereof is unnecessary, and will be understood by those ordinarily skilled in the art. It is, however, helpful to highlight a few of the benefits of carbon nanotubes in order to put the advantages of the present invention in proper context. One benefit of carbon nanotubes is their ability to exhibit electrical properties of semi-conducting or metallic materials, depending on chirality, and to exhibit varying electrical properties depending on tube diameter. Another benefit is their ability to form efficient nanoscale machines due to the low coefficient of friction between an inner carbon nanotube and an outer carbon nanotube during either or both of linear and rotational relative motion. Yet another benefit is the high tensile strength of carbon nanotubes (especially combined with the low density of carbon nanotubes) relative to other available fibers.
Despite such beneficial properties, integration of carbon nanotubes into commercial products is currently problematic, and has, therefore, not become wide-spread, due to shortcomings associated with conventional methods of manufacture thereof, including laser-ablation, arc-discharge, and chemical-vapor-deposition (CVD) techniques. Specifically, conventional methods of manufacture for carbon nanotubes suffer, to varying degrees, from one or more disadvantages, such as high energy usage, random structural formation (including random dimensions, wall-structure, and chirality) and the associated need for manual sorting, consumption of catalyst materials, inter-mixture of waste or by-products with the carbon nanotubes and the associated need for cleaning, occurrence of defects in manufactured carbon nanotubes, limited length of manufactured carbon nanotubes, and limited batch size. These disadvantages, among others, result in high costs of manufacture for carbon nanotubes and fail to provide a viable method for large-scale manufacture of carbon nanotubes, especially for those having lengths in the millimeter range or larger.
As such, it is clear that there is an unmet need for a system and method for manufacturing carbon nanotubes whereby selection of the diameter, length, chirality, and wall structure of individual carbon nanotubes formed thereby is enabled. Such a system and method will preferably enable selective manufacture of carbon nanotubes having predetermined properties, including physical, electrical, optical, and thermal properties, among others, whereby a consistent supply of identical carbon nanotubes may be provided for integration into or production of commercial products.